Influence of bismuth on magnetism and magnetocaloric properties of LaFe_(11.6)Si_(1.4) intermetallic compound  

作　　者：A.Boutahar K.Zehani L.Bessais H.Lassri E.K.Hlil 

机构地区：[1]LPMMAT,Hassan II University-Casablanca, Faculty of Science Ain Chock, BP 5366, Maarif-Casablanca, Morocco [2]ICMPE-CMTR, UMR CNRS 7182, 2-8, H. Dunant St, 94320 Thiais, France [3]Néel Institue, CNRS and Joseph Fourier University

出　　处：《Journal of Rare Earths》2015年第7期740-745,共6页稀土学报（英文版）

摘　　要：Crystal structure, magnetic properties and magnetocaloric effects （MCE） of La1-xBixFe1 1.4Si1.6 （x=0.0 and 0.1） compounds were investigated by X-ray diffraction and magnetization measurements. The La1-xBixFe11.4Si1.6 compounds presented a cubic NaZnx3 type structure. First, the magnetization behavior and the magnetic transition were analyzed in terms of Landau theory. Then, Bi substitution for La in La1-xBixFe11.4Si1.6 compounds led to a decrease in magnetic entropy change （-△SM^max） but an increase in Curie temperature （Tc） significantly. The significant increase of Tc by Bi substitution from 202.5 to 256 K for x=0.0 and x=0.1 respectively was attributed to an increase in the Fe-Fe exchange interactions. Moreover, magnetocaloric effect was calculated in terms of isothermal magnetic entropy change. The maximum values of （-△SM^max ） of La1-xBixFe11.4Si1.6 for x=-0.0 and 0.1 compounds were found to be, respectively, 22.56 and 4.36 J/（kg.K） under an applied magnetic field change of 5 T. For the same applied magnetic field （μ0H=5 T）, the relative cooling power （RCP） values were found to vary between 487 and 296 J/kg.Crystal structure, magnetic properties and magnetocaloric effects （MCE） of La1-xBixFe1 1.4Si1.6 （x=0.0 and 0.1） compounds were investigated by X-ray diffraction and magnetization measurements. The La1-xBixFe11.4Si1.6 compounds presented a cubic NaZnx3 type structure. First, the magnetization behavior and the magnetic transition were analyzed in terms of Landau theory. Then, Bi substitution for La in La1-xBixFe11.4Si1.6 compounds led to a decrease in magnetic entropy change （-△SM^max） but an increase in Curie temperature （Tc） significantly. The significant increase of Tc by Bi substitution from 202.5 to 256 K for x=0.0 and x=0.1 respectively was attributed to an increase in the Fe-Fe exchange interactions. Moreover, magnetocaloric effect was calculated in terms of isothermal magnetic entropy change. The maximum values of （-△SM^max ） of La1-xBixFe11.4Si1.6 for x=-0.0 and 0.1 compounds were found to be, respectively, 22.56 and 4.36 J/（kg.K） under an applied magnetic field change of 5 T. For the same applied magnetic field （μ0H=5 T）, the relative cooling power （RCP） values were found to vary between 487 and 296 J/kg.

关 键 词：NaZn13 itinerant-electron metamagnetic transition magnetocaloric effects rare earths 

分 类 号：TG132.2[一般工业技术—材料科学与工程]